Will Davis - Copyright 2010. Nuclear energy news, insight and analysis. Coverage of events world wide, including new plant construction, operation of plants now in service, and shutdown and decommissioning of plants. APR emphasizes the technology of nuclear energy, as well as the history of the development of that technology. Your #1 nuclear energy source!

APR: your source for nuclear news and analysis since April 16, 2010

Wednesday, April 6, 2011

Wednesday morning update...

All the wires are still running the story (backed up by official information) that the high-rate leakage of highly contaminated water into the sea off Fukushima Daiichi has stopped and not restarted. TEPCO is analyzing the situation; one has to assume that there's the chance another source could occur... and this is probably, given the circumstances, very prudent. But this is a glimmer of sunshine for TEPCO. In terms of numbers, TEPCO has stated that it injected 6000 liters of the coagulant solution into the ground.

The water situation, that is to say the movement of and/or disposal of low-level contaminated water in order to make room for the high-level contaminated water in No. 2 building continues. Water continues to go to sea from the radwaste facility; the last figure I heard very late last evening was that TEPCO considered it might have put out over 6300 tons of water so far at that point from just that facility. Since I have not run the total figures here yet, let's just look at a couple of the mentioned storage places and figures.

First, TEPCO thinks there might be as much as 20,000 tons of water in each of the three turbine buildings, Nos. 1 through 3, maximum. That in No. 2 is highly contaminated, giving a total just in the plants there of 20,000 tons (max) highly contaminated which you cannot discharge, and 40,000 tons of less contaminated water.

The main condensers have been used as temporary storage, or transfer, sites but the condenser at No. 1 plant holds only 1600 tons of water, while the condensers in the other three plants hold 3000 tons each. The radwaste building can hold up to 30,000 tons of water, and it's in the process of being emptied right now. The 'mega barge' which we've described before should be the next available large storage facility with a capacity of about 18,000 tons max; there are also plans forming to very rapidly build or ship in extra large storage tanks for use on-site with a cumulative capacity of about 27,000 tons. Considering all the capacity available and on the way it appears as if TEPCO will be able to handle all this with the stipulation that water discharge to sea is still allowed for some low-level water.

We didn't mention No. 5 and No. 6, which need to pump the low-level water out of their turbine building drain pits to sea.

The media frenzy over the "7.5 Million Times the Limit" reading continues; luckily, regular readers here are not overly alarmed.

Speaking of things not to get too overly alarmed about: TEPCO is now saying that it might not only inert the drywell and containment spaces in No. 1 plant, but might do it at No. 2 and No. 3 plants as well. We first mentioned this at 6 PM Sunday evening here, regarding No. 1 plant and it appears that while it hasn't been done yet TEPCO might extend this explosion-prevention method to all three plants which have cores installed. TEPCO thinks there's liberated hydrogen in there, either from radiolysis or metal-water, and NISA seems to think that at least No. 2 and No. 3 reactor pressure vessels are no longer pressure tight. (They've been saying this off and on for a while, and JAIF seems to agree.) I myself have questioned pressure vessel integrity on all three plants for a long time now and think nitrogen inertion of all available spaces around the reactor plants, inside the reactor buildings is a wise idea. Perhaps overly precautionary, but wise. Wise enough to do today, unless radiation levels, debris or damage are preventing them from accessing a location to do so.

3 comments:

Excellent factual reporting. As usual I wish the mainstream media were that in this incident instead of molding public perceptions like mingling images of quake damage with those of Fukushima as though it were somehow responsible -- and alarmingly many believe that! Nuclearphobia has run so off the wall that there are even protests welling against the recently proposed joint U.S.-Russian deep space nuclear-powered spacecraft! The leaks may stop but the gushing of agenda-driven media misinformation, exaggerations and ominious speculations of this event continues and I really wish someone would challenge them every step of the way from steering the nuclear policy of this country and the world with rabid fear.

Btw, did a couple of quick back of the envelope calculations yesterday just to quantify things for myself a little.

Take a half cylinder of radius 15km and depth of 10m (Anyone have an idea of the average sea depth out there?) this gives us a volume of water of about 3.5 billion cubic meters. If you evenly dissolved slightly under 500 tons of water at 7.5 million times the limit the entire body of water would end up at the limit.

If you take 1km and 10 meters giving slightly under 16 million cubic meter of water then just over 2 tons dispersed evenly would leave the overall body of water at the limit.

Now that is nearly meaningless as the highly irradiated water will not disperse evenly and while this is probably fine for Iodine Caesium will accumulate on its way up the food-chain etc but it does give a little perspective.

Anyway it would be nice to have some better estimates of how much of the highly contaminated water leaked out and how it is dispersing.

Btw, whilst it isn't it is nowhere near as bad as media reports make out it would be nice to get some better upper and lower bounds etc. At the moment it is easy for the media to go into frenzy mode because what they hear is "safe" limits being raised with few attempts to explain the reasoning behind either the old or new limits. The "there is little to be worried about" just sounds like whitewash against that kind of background. That these releases are cause for concern is very clear but it's difficult to keep worst case scenarios out of your mind when you have so few hard facts on the possible impact of these things.

Essentially you have people who can paint a clear picture of a worst case scenario, some people who say that there is nothing to worry about etc and lots of concerned people who are unable or unwilling to put forward a range of plausible outcomes (mostly because these people know how little they know but that isn't very helpful at this point...).

Did you have a look at the NY times last article ?it is here : http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html?_r=1&ref=global-homeI get the fact that salt may come in the way of emergency cooling duct (I suppose fire extinguishing inlet is located higher in the vessl)I also can understand why filling the whole vessel with water can raise problems with earthquake (they are supposed to be filled for every refueling right ?)The part I don't understand is the "suspicion" that some fuel elements in the pool of #3 may have been projected up to one mile on the explosion : Such a hot source should be easily detectable by a gamma camera on a drone, no ?